Device for grinding pilot holes in circular chasers



March 27, 1934 w. J. HOGG 1,952,207

DEVICE FOR GRINDING PILOT HOLES IN CIRCULAR GHASERS Filed Aug. 14, 1931 Patented Mar. 27, 1934 more STATES DEVICE FOR GRINDING PILOT HOLES IN CIRCULAR CHASERS William J. vi-logg, Gleveland, Ohio, assignor to The National Acme Company, Cleveland, Ohio,

a corporation of ()hio Application August 14,

9 Claims.

This invention relates to a grinding fixture for use with circular chasers of threading dies for the purpose of grinding the pilot holes in such chasers, the object being to provide a simple, inexpensive and effective fixture whereby the pilot holes in the circular chasers will be accurately ground.

In the drawing accompanying and forming a part of this specification- Fig; 1 is a-top view thereof;

Fig. 2 is a partly cross-sectional view taken on line 22 of Fig. 1;

Fig. 3 is a cross-sectional view taken 3-3 of Fig. 2; and

Fig. 4 is a top view of one of the button carrying jaws.

Similar characters of reference indicate corresponding parts in the several views.

Before explaining in detail the present improvement and mode of operation thereof, I desire to have it understood that the invention is not limited to the details of construction and arrangement of parts which are illustrated in the accompanying drawing since the invention is capable of other embodiments, and that the phras'e'ology which I employ is for the purpose of description and not of limitation.

The present improvement comprises a supporting member or block 2 having ways 3 for the reception of jaws 4 shown in the present instance as three in number, provided with concaved ends 5, the ends being concaved to permit the proper closing of the chucks or jaws.

Adjustably carried by each of these jaws is a member or button 6 having a V-shaped head '7, that is each head has a single circular tapered or V-shaped edge, these buttons being suitably clamped in the ways of the jaws by means of bolts and nuts 8 and all circularly located with their axes spaced equally from the axis of the work. As the adjustable buttons have but a single V-shaped rib, it will be apparent that they can be used with a chaser having any desired number of threads, twelve per inch, sixteen per inch, or any other number, whereas if they had more than a single V-shaped rib it would be necessary to provide buttons to correspond with the number of threads on each chaser to be ground.

For adjusting the buttons a micrometer screw 9 is carried by each of the jaws and by this means the buttons may be adjusted toward and from the circular chaser, to properly support the same and different sizes thereof, so that the V-shaped heads will fit the circular grooves of the chasers. Thus the chaser is supported in proper relation to on line 1931, Serial No. 557,101

the pitch diameter thereof, the buttons being adjustable for different diameters and pitch of the When it is desired to grind several chasers of the same set, they being each uniform in pitch diameters, it is only necessary to set the buttons 6 for the first chaser and then by withdrawing the jaws 4 that chaser may be removed and others inserted and the jaws 4 again closed.

The pilot of the circular chaser is accurately ground and therefore the pilot hole-must be likewise accurately ground to snugly fit the pilot in order that there will be no lateral movement when the chasers are reground as clearly described in my contemporaneously pending application Serial No. 555,210, filed August 5, 1931.

In the present instance, the buttons are shown attached to chuck jaws such as spring chuck jaws of a suitable grinder and when the first piece is properly set between the buttons so that the chasers run true then the spring chuck jaws are closed and the buttons are tightened by screws provided for that purpose extending through the buttons and the nuts on the bottom thereof located in the T-shaped slots of the jaws, and are held tight. Then, when it is desired to insert a new chaser, the jaws of the chuck can be opened, allowing the first piece to be removed and the second piece inserted for grinding as the buttons do all the holding of the chaser by reason of their engagement thereof in the thread grooves of the chaser, thus holding the chaser true so that the pilothole will be ground true with the threads.

It is to be understood that, by describing in detail herein any particular form, structure or arrangement, it is not intended to limit the invention beyond the terms of the several claims or the requirements of the prior art.

Having thus explained the nature of my said invention and described a way of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the modes of its use, I claim:

1. A grinding fixture for grinding the pilot holes in circular chasers comprising a supporting block, a plurality of radially adjustable members operable to open and close in unison and a second set of radially adjustable members each having a single circular V-shaped head, adapted to fit the grooves of a chaser, carried by said first adjustable members.

2. A grinding fixture for grinding the pilot holes in circular chasers comprising a supporting block, a plurality of radially slidable members operable to open and close in unison, a second set of radially adjustable members each having a single circular V-shaped head adapted to fit the grooves of a chaser and carried on top of said first adjustable members, and means for adjusting said last set of adjustable members.

3. A grinding fixture for facilitating the grinding of the pilot holes in circular chasers comprising a supporting block having ways therein, a plurality of radially adjustable members operable to open and close in unison, and a second set of adjustable members each having a single circular V-shaped head, adapted to fit the circular grooves of a chaser, carried by said first adjustable members and means for securing said last means in fixed position.

4. A grinding fixture for facilitating the grinding of pilot holes in circular chasers consisting of a supporting member having a series of jaws operable to open and close in unison, and a series of buttons adjustably supported on said jaws, and means for adjusting each of said buttons.

5. A grinding fixture for facilitating the grinding of pilot holes in circular chasers consisting of a supporting member having a series of jaws operable to open and close in unison, and a series of buttons adjustably supported on said jaws, and means for adjusting each of said buttons, each of said buttons having a V-shaped head.

6. A grinding device for insuring the true grinding of the pilot hole of circular chasers and consisting of a supporting block, a series of three adjustably supported buttons carried thereby and having V-shaped heads all equidistantly located from the bottoms of the buttons, and means operable to open and close in unison for securing said buttons at the same distance from the center of the block.

7. A grinding fixture for grinding the pilot hole in circular chasers comprising a supporting block, and a plurality of adjustable members having V-shaped heads adapted to fit the grooves of a chaser, said adjustable members being carried by sliding jaws operable to open and close in unison.

8. A grinding fixture for facilitating the grinding of pilot holes in circular chasers consisting of a supporting member having a series of jaws operable to open and close in unison, a plurality of adjustable members carried by said jaws, said adjustable members having V-shaped heads adapted to fit the grooves of a chaser, and means for clamping said members in fixed position.

9. A grinding fixture for facilitating the grinding of pilot holes in circular chasers comprising a supporting member having a plurality of slidable jaws operable to open and close in unison and a plurality of buttons corresponding with the number of the jaws and carried by said jaws and adjustably supported thereon, means for adjusting each of said buttons, each of said buttons having a V-shaped head adapted to engage a thread groove of a chaser. a

WILLIAM J. I-IOGG. 

